Combined end plate and brush holder support for dynamo-electric machines



Aug. 30, 1932. L, EHRUCH 1,874,000

coMBINED END PLATE AND BRUSH HOLDER SUPPORT FOR DYNAMO ELECTRIC MACHINES Filed June 4, 1928 mmww w.

Patented Aug. 30, 1932 UNITED STATES PATENT OFFICE LOUIS B. EHRLICH, OI TOLEDO, OHIO, ASSIGNOR TO THE ELECTRIC AUTO-LITE COI- PANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO COMBINED END PLATE AND BRUSH HOLDER SUPPORT FOR DYNAMO-ELEC'IBIC MACHINES o Application filed June 4. 1928. Serial No. 882,815.

This invention relates to dynamo-electric machines and more particularly to brush supporting structures for use with those of the type such as are commonly employed as part of the electrical equipment of motor vehicles.

In the manufacture of starting motors and generators for use in conjunction with automotive vehicles it has heretofore been the practice to provide an end frame structure therefor to which is attached or secured, by various means, a separate plate which carries the commutator and brush holders. As the end frame structures heretofore have been made Qfcastings upon which expensive machining or finishing operations must be performed, the resulting structure is comparatively expensive and assembly of the component parts is rendered diflicult.

It is one of the principal objects of this in- 80 vention toprovide a combined end frame structure and brush supporting member for use with a dynamo-electric machine.

Another object is the provision of a combined brush holder support and bearing for the armature shaft of a dynamo-electric machine.

Another object is the provision of a combined brush support and end frame for enclosing a structure of this character in which a considerable saving of material is effected.

Still another object is the provision of improved means for supporting and guiding the commutator brushes of a dynamo-electric machine.

A further object is the provision of a structure of this character having the parts so arranged as to facilitate assembly of component parts whereby a material saving in time and labor is effected.

Still a further object is the provision of a combined sheet metal brush holder and an enclosing structure for the housing of the dynamo-electric machine in which locating means are formed out of the sheet metal structure so as to position the brushes with combined commutator brush support and end frame structure of my invention;

Figure III is -a detail sectional view of the parts shown in Figure II; a

Figure IV is a fragmentary detail sectional view taken substantially on the line 44 of Figure II.

Referring to the drawing in detail, I have shown the structure of my invention as im corporated in a starting motor adapted for use in initiating the operation of an internal combustion engine, but it is to be understood that I contemplate the use of this structure wherever the same may be found to be ap- '5 plicable. The starting motor with which I have shown my invention comprises a cylindrical housing 5 within which is revolvably supported an armature 7, an extension of the armature shaft 8 being provided with a go threaded portion 9 on which is mounted a starting pinion 10 adapted for enmeshment with a flywheel gear 11 under certain conditions. The end of the motor housing adjacent the pinion 10 is provided with a suitable as inclosure 13 which is secured to a frame structure 12 forming a part of the internal combustion engine frame and serves as a suitable support for the starting motor.

The other end of the motor housing 5 is .0 adapted to be inclosed by a combined sheet metal end frame structure and brush support of my invention which will now be described in detail.

Referring particularly to Figures II and III, the structure comprises substantially a circular plate 15 which is preferably formed of sheet material and is provided with a plurality of projections 17 which may be separate members secured to the plate and in I any suitable manner which are illus'trated as struck up or-formed out of'the body. of the i plate 15. These projections are radially dis- .posed with respect to a hub portion 18 formed out of the sheet metal plate 15, and serve to locate the" end frame structure properly with respect to the motor housing. The hub 18 is adapted to. snugly receive a bushing 19 which forms a suitable bearing for the armature shaft 8. This bushing may-be of any suitable material, but I have found that one constructed with bronze and lined with graphite serves the purpose very effectively.

It is highly essential that the pro'ections 17 be formed with their surfaces su stantially equidistant from the axis of the hub portion 18 as it is imperative that a structure of this kind must positively retain the armature in a central osition with respect to the field magnets oi the machine in order to insure a constant and uniform pull upon the motor armature by the field magnets. .If the bearing supporting the armature shaft is eccentric with respect to the radial distance of the field poles and the axis ofthe armature, the magnetic flux on one side will be greater than upon the other. Furthermore, if an eccentric condition exists in a device of this character, so that the armature is. nearer one side-of the field magnets than it is another, the force exerted by the field magnets that are nearer to the armature will cause the bearing to be worn on one side.

The plate 15 is formed with an annular raised portion 20 which form's a suitable supporting base for the brush holders. In the particular embodiment shown, I have employed pairs of brushes 21 and 22 which are adapted to engage the commutator 23 of the armature 7, t ese projections being preferably arranged degrees apart. The brushes 21 are adapted to be grounded to the plate 15 while the brushes 22 are adapted to be connected to the field coils'(not shown) of the armature to complete the motor circuit. The grounded brushes 21 are adapted to be slidably positioned within formed sheet metal brackets 26,v the projecting ends 27 of which are split to receive and retain springs 28 adapted to engage the brushes and'hold them in engagement with the commutator. Interposed between the brackets 26 and the raised portion 20 of the plate 15 are the sheet metal bars 30 to which the leads from the brushes 21 are soldered or otherwise secured in order to ground these brushes. The brackets 26 and bars 30 aresecured to the plate 15 bymeans of a plurality of rivets 32. The brushes 22 are supported and adapted to be guided by brackets 33 identical in construction with the brackets 26, and are also provided with springs 34 for holding the brushes in engagement with the commutator. Interposed between the brackets 33 and the plate 15 are the strips 35 of suitable insulating material, the brackets and insulating.

strips beingsecured to'the plate'15 by means of rivets, which are also insulated from the late by means of small collars (not shown}. he brushes 22 -areconnected by suitab einsulated lead wires 37 to the field coils of the dynamo-electric machine. The metal 'bars 30 and the insulating strips 35 interposed between the brackets 26 and. 33 are of substantially the same thickness so that the brushes will be caused to engage the same portion of the commutator 23 and thus prevent an uneven wearing of the commutator which would be caused by a disali gnment of the brushes. It" will be obvious from the foregoin description that the several brush holders, rushes and springs are all of the same construction and thebrush holders are secured to the plate by like means which obviously makes a simplified and durable construction in which the cost of assembling the parts is reduced to a minimum.

It is apparent that, within the scope of the invention modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending, all variations thereof.

What I claim is:

1. In a device of the character disclosed, in combination, a sheet metal'end frame member for a dynamo electric, machine, said'sheet metal end frame supporting a hub portion carrying an armature bearing; a plurality of integrally struck up projections substantially equi-distant from said hub portion, said member having a raised portion'radially spaced from said hub portion; and a plurality of brush holders supported by said raised portion, said brush holders being centrally disposed with respect to said hub.

2. A cover for a' substantially tubular dynamo electric machine casing, said cover having a sheet metal body, portions support ing a hub portion provided with a plurality of integrally struck up projections centrally -metal end ccver for said casing adapted to carry a bearing for the armature shaft; a plurality of struck up projections substantially equi-distant from the axis of said bearing and adapted to engage the inner wall of said casing for centrally positioning said bearing with respect to said pole pieces; said sheet metal end cover having a raised portion; a

plurality of brackets carried by said raised portion, said brackets adapted to support commutator brushes, each of said brackets being substantially centrally positioned with respect to said bearing.

4. In a dynamo electric machine, the combination of a casing having a plurality of pole pieces; an armature having a commutator and a shaft mounted to rotate in said casing; a sheet metal end cover for said casing having a portion adapted to carry a bearing for the shaft of said armature; aplurality of struck up projections substantially egui-distant from the axis of said bearing and a apted to engage the inner wall of said casing for centrally positioning said armature with respect to said pole piece faces, said sheet metal end head having a raised projection; a plurality of U-shaped brackets supported on said plate and carried by said raised portion, said bracket adapted to support a commutator brush; a spring secured to said bracket for engagement with said brush, and said brackets being substantially centrally positioned with respect to said bearing whereby each of said springs exerts a substantially uniform pressure on each brush in contact with the armature commutator.

5. In a device of the character disclosed, in combination, a sheet metal end frame member for a dynamo electric machine casing, said sheet metal end frame supporting a hub portion carrying an armature bearing; a plurality of cup-shaped integrally struck up projections forming a mutilated flange for properly positioning said hub portion with respect to the dynamo casing, said end frame member having a raised portion radially spaced from said hub portion; and a plurality of brush holders supported by said raised portion, said brush holders being centrally disposed with respect to said hub.

6. In a dynamo electric machine, the combination of a casing having a plurality of pole pieces an armature having a commutator and shaft mounted to rotate in said casing; a sheet metal end cover for said casing ada ted to carry a bearing for the armature sha t; a plurality of struck up projections of a substantially cup-shaped confi uration adapted to engage the inner wall 0 said casing for properly positioning saidbearing with respect to said pole pieces; a plurality of brackets centrally spaced from said bearing, said brackets adapted to support commutator brushes. 1

In testimony whereof, I ailix my si ature.

LOUIS B. EHRL OH. 

